Photographic objective for precision copying



350-464 5R ARCH ROOM OR -581115ifti?" HOQT x wibfi J n 17, 1969 AKIRAQYASQIDA 3,450,463

PHOT OGRAPHIC OBJECTIVE FOR" PRECISION COPYING Filed Sept. 1. 1965 SPHERICAL ABERRATION ASTIGMATISM DISTORTION INVENTOR. AKIRA )fisqm J1 roquaf length of the objective.

United States Patent Other: A

PRECISION 2 Claims ABSTRACT OF THE DISCLOSURE An objective lens for copying comprising two single element front components and four rear components totaling seven elements,'the objective having an aperture ratio of F/ 1.2.

This invention relates to a photographic objective fo precision copying.

Photographic objectives for copying, particularly microcotpying, must be superior in resolving power, since their reduced images. are required to be extremely sharp.

This invention contemplates providing a photographic objective for copying, and comprises two front components, each of one element, and four rear components of a total seven elements. With this invention, aberrations such as coma, astigmatism and curvature of image field are highly and effectively corrected. Providing such high degree of correction for these aberrations results in successful realization of an objective system which has an aperture ratio of F/ 1.2 and a resolving power substantially equal to a resolving limit determined by ing drawing in which:

FIG. 1 is a sectional view of a photographic objective for precision copying embodying the invention; and FIG. 2 shows the graphs of spherical aberration, astigmatism and distortion of the photographic objective having a focal length designated as 100 mm.

copying being used in the range of 4800 A.-6500 A. wavelengths, required corrections for chromatic aberration may to some degree be mitigated; but, it is necessary to observe a drastic practice of corrections on the basis of oblique light rays for such aberrations, among others,

as coma, astigmatism and curvature of image field, should the resolving power be made powerful enough to approxi-,

mate the limits set by the diflraction phenomenon. Condition (l) of the first component 1. may work so that both surfaces of the prescribed radii of curvature, respectively, should negate each other the adverse infiuences on the corrections for oblique light rays for astigmatism and curvature of image field. The upper limit of the condition signifies the degradation extreme of astigmatism and curvature of image field in the negative direction while the lower limit thereof those in the positive direction.

In addition to condition (1) given to component L condition (2) given to the radius of curvature of element L one of the rear components, serves considerably to correct for coma as well as for spherical aberration. Furthermore, condition (3) on the relation of the radii of curvature and the central thickness of component L serves fully for effective correction for both astigmatism and curvature of the image field in addition to correction for image distortion. Successful corrections of such In the objective system in accordance with the invention, referring to FIG. 1, the first component L is a negative meniscus with the concave surface toward the object, the second component 1., a positive element, the

1 third component L L and L a cemented negative comface of the fifth component L is between 0.6 f and 1.5 v f;

and

(3) The ratio of the curvature r of the object-side face of the sixth component L to the sum of the curvature r of its image-side face and its'optical axis thickness d lies between 0.3 and 1.0; where f is the focal The inventive photographic objective for precision graphic objective for copying 'with extremely high re-* solving power of a total of 1,000 lines in a 1 mm. wide area at a magnification of 1/ 25.

A photographic objective as a form of embodiment of the invention is illustrated in FIG. 1. Two numerical examples of the illustrative embodiment of FIG. 1 are below given, where 8 denoting the reduction rnagnification, 1 the overall focal length; r, d, h and v respectively, the radius of curvature, the thickness of the element or the air spacing between elements, except d which is the object distance, the refractive index and the Abb number. It is noted that in the following Examples 1 and 2 9 is preceded by a minus sign which means inverted image.

EXAMPLE 1 (Data) [fl.=0.04 f=1001 d =2,006.767 I. 0 Ti= 150.037

di=16.943 1. 74687 27. 7 Tz=200.400

d4=487.970 1 r =+290.546 d5=22.026 1. 44850 67. 0 n 117.350

du=5.083 1. 69402 31. 2 f7=+525.246

d7=9.l49 1. 69451 54. 8 fa= '4,676.381

. (1 :3.049 1. 0 fe=+l05.330

d =17.079 1. 02598 57. 9 n a:

d1o=2.440 1'. 0 111=+95.730 I d =17.282 1. 59865 39. 3 Tn=+60.996

dn=22.026 1. 43498 94. 9 f13=+3,388.682

d|3=1.627 1. 0 T14=+4L35Z tii4=52.321 1. 51871 04. 1 T t=+26.330

Patented June 17, 1969 Seidel coefficients for the two examples of the invention are as follows, where I, 'H, 11H, 1V and V in the table denote, respectively, the spherical and the comatic aberration, curvature of meridional image, curvature of sagital image and distortion.

With respect to Example 1:

FIG. 2 which illustrates curves of spherical aberration,

I II III IV V 11--.- 0 0204190 0.1855268 -'5.1572380 -1. 7858697 17. 9050106 18-..- 0 0014546 0. 0151618 0.5490924 0.2330368 4 2130868 72---- 0 0052820 0. 0069282 0. 0452220 0. 0270468 -0 0340920 11-... 0.0006884 -0. 0095876 0.4185096 0.1514760 2 0422458 11--.- 0 0024084 0. 0154704 0. 8355710 0.1368350 0 9170488 r.--" 0 0677056 0. 0264852 0. 0610588 0. 0408378 0 0105240 n 0 0000014 0. 0000104 0. 0002168 0. 0000798 0 0004694 11.... 0. 0000094 0. 0011412 0. 0016738 0 6573066 111.... 0. 0199022 0.0909288 1 3281950 0 4973112 3 8513870 no..- 0.0105326 0. 0298402 0 2536212 0 0845405 0 0709502 m.-. 0. 0004730 0.0023582 0.1699390 0 1464294 1 7452728 711... 0. 0101474 0 0388698 -0. 4877948 0 1900124 1 0140052 715... 0.0452280 0 0300114 0.0565976 0 0167692 0 0158426 714... 0. 0026136 0 0130024 0.0963578 0 2257214 4 3142912 m... 0.0153812 0 1202268 2.3631616 0 4836776 2 6133936 With respect to Example 2:

I II III IV v 41--.- 0. 0221570 0.1917988 5. 0922836 -1. 7717496 16. 7705988 15.-.. 0.0017554 0. 0174060 0.6013530 +0. 2561758 4. 0706004 73-.-- 0. 0053600 -0. 0058276 0. 0391120 0. 0264402 -0. 0270014 71.... 0. 0006782 -0. 0092118 0. 8945462 0. 1443650 1. 9019846 m-.- 0. 0024170 0. 0152760 0. 3311408 0. 1380436 0. 9172550 r.-." 0. 0674866 0. 0250204 0. 0606478 0. 0420954 -0. 0115050 r1.-.- 0. 0000022 0. 0000134 0. 0002530 0. 0000940 0. 0005106 n 0 -0. 0000092 0. 0064432 0. 0044m 0. 6656546 19-.-- 0. 0197460 0. 0888812 1. 2908844 0. 4907400 2. 2992196 11.... 0. 0110716 0. 0308514 0 2496118 0. 0832038 -0. 0 05182 m--. 0.0001808 0 0008888 0 1622608 0.1635230 1 6845782 m.-- 0. 0100430 0 0378424 -0 4733234 0 1881388 -0 968711 m.-- 0.0467970 0 0300793 0 0545202 0.0158514 0 0138208 m--. 0. 0034402 0 0168746 0 0732616 0.2388056 4.05 7764 1"... 0.0152726 0. 1208364 2 3518630 0 4397626 26489800 negative meniscus with its concave surface toward the object, the sixth component 1. being a positive meniscus with its concave surface toward theimage, the arrange ment of lenses satisfying the following conditions:

Overall focal length: f= Reduction magnification: 5: 0.04 (inverted image) where n denotes the refractive index. for the e-line of the spectrum of the successive lenses and air spaces therebetween in their order from the object to the image side of the objective; r subscript the radius of curvature of the lenses in such order; d subscript the thickness of the lens component or the air spacing therebetween in such order on the optical axis, except that d is the distance to the object, and v theAbb number of the lenses in such order. p

2. A photographic objective for precision copying comprising a first lens component L a second lens component L a third lens component consisting of cemented lenses L L and L a fourth lens component L a fifth lens component consisting of cemented lenses L and L and a sixth lens component L the first component being a negative meniscus with its concave surface toward the object, the sixth component L being a positive meniscus with its" concave surface toward the image, the arrangement of lenses satisfying the following conditions:

Overalltocal length: f=100 Reduction magnification: B=-0.03766 (inverted image) d2=19.484 1. 0 r =746.191 i ds=51.404 1. 60752 28. 1 n=-778.319

d5=22.455 1. 44850 67. 0 fs= 121.021

. 5 d7=9.327 1. 69451 54. 8 rg=4,767.733

=3.109 1. 0 f9=168.540 d =17.411 1. 62598 57. 9 T 0= g d10=2A87 1. 0 T =99.665

d ;=22.455 1. 43498 94. 9 f s==3,454.589

d =1.658 1. 0 fu=42.150

5 6 where n denotes the refractive index for the e-line References Cited of the spectrum of the successive lenses and air spaces UNITED STATES PATENTS therebetween ,in their order from the object to the image 3,174,396 3/1965 Ruben 5 X side of the objectlve; r subscript the radius of curvature 5 FOREIGN PATENTS of the lenses in such order; d subscript the thickness 315,159 9/ 1956 Switzerland. of the lens component or the air spacing therebetween 1 in such order of the optical axis, except that d is the JOHN CORBIN, Primary Examinerdistance to the object, and v the Abb member of the CL lenses in such order. 10 350215 

